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Method for Calibrating Modeled Ammonia Fill Levels

A filling level, modeling technology, applied in the direction of electronic control of exhaust gas treatment device, diagnostic device of exhaust gas treatment device, machine/engine, etc. limit value etc.

Active Publication Date: 2022-04-15
ROBERT BOSCH GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] However, it may happen that the physical ammonia fill level in the second or downstream SCR catalyst deviates from the modeled ammonia fill level
When the physical ammonia filling level is too low, the nitrogen oxide conversion rate of the second SCR catalytic converter is reduced and the limit value may be exceeded
Although the quick adaptation method can recalibrate the NOx target value downstream of the second SCR catalyst, it is still difficult to eliminate the cause of the error, because the adaptation method cannot determine whether it should be in the area of ​​​​the first SCR catalyst or in the area of ​​​​the second SCR catalyst Find the cause of error in

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  • Method for Calibrating Modeled Ammonia Fill Levels
  • Method for Calibrating Modeled Ammonia Fill Levels
  • Method for Calibrating Modeled Ammonia Fill Levels

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Embodiment Construction

[0020] The internal combustion engine 10 has an SCR catalytic system 20 in its exhaust line 11, such as figure 1 shown. The SCR catalytic system has a first reducing agent dosing unit 41 with which an aqueous urea solution can be injected into the exhaust line 11 . At the high temperature of the exhaust gases, ammonia is released from the aqueous urea solution. A first or upstream SCR catalyst 21 and a second or downstream SCR catalyst 22 are arranged downstream of the first reducing agent metering unit 41 . The catalyst material of the first SCR catalytic converter is arranged on a particle filter (SCR on filter; SCRF). The first NOx sensor 31 is arranged in the exhaust line 11 upstream of the reducing agent dosing unit 41 . The second NOx sensor 32 is arranged between the two SCR catalytic converters 21 , 22 . A third NOx sensor is arranged downstream of the second SCR catalyst 22 . A second reducing agent metering unit 42 is arranged between second NOx sensor 32 and se...

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Abstract

The invention relates to a method for correcting a modeled ammonia filling level of a downstream SCR catalytic converter (22) in an SCR catalytic system (20) having two successively arranged in an exhaust line (11) The SCR catalytic converter (21, 22). The expected mass flow of nitrogen oxides downstream of the downstream SCR catalyst ( 22 ) is compared to the mass flow of nitrogen oxides measured downstream of the downstream SCR catalyst ( 22 ). Make corrections based on comparison results.

Description

technical field [0001] The invention relates to a method for correcting a modeled ammonia filling level of a downstream SCR catalytic converter in an SCR catalytic system having two SCR catalytic converters arranged one behind the other in an exhaust tract. Furthermore, the present invention also relates to a computer program for executing each step of the method, and a machine-readable storage medium storing the computer program. Finally, the invention relates to an electronic control unit, which is configured to carry out the method. Background technique [0002] Selective catalytic reduction (Selective Catalytic Reduction; SCR) with the aid of ammonia or ammonia decomposing agents is a promising method for reducing nitrogen oxides in oxygen-rich exhaust gases. The efficiency of an SCR catalyst depends on its temperature, the space velocity of the exhaust gas and, crucially, the filling level of ammonia adsorbed on its surfaces. In addition to the directly dosed ammonia,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F01N11/00F01N3/20F01N9/00
CPCF01N11/00F01N3/2066F01N13/0093F01N9/005F01N2550/02F01N2560/026F01N2900/1402F01N2900/1621F01N2900/1622Y02T10/12Y02T10/40F01N9/00F01N2610/02
Inventor F.施魏策
Owner ROBERT BOSCH GMBH